1. Field of the Invention
The invention relates to a method for generating ozone and a device for generating ozone.
2. The Prior Art
Ozone is a strong oxidizing agent for organic substances and for inorganic compounds in which elements having several oxidation stages are present. Of the numerous applications for this oxidizing agent, over the last few years applications for water treatment in particular have been intensively further developed.
Ozone is generated by electric discharge in an oxygen-containing gas. The so-called silent discharge represents a stable plasma or corona discharge in contrast to the spark discharge. In this case molecular oxygen is dissociated into atomic oxygen. The reactive oxygen atoms thus formed are added to the existing oxygen molecules in an exothermic reaction and thus form the tri-atomic ozone molecule.
Important parameters for the efficiency of the overall reaction chain are the gas composition, the electric field strength, the operating temperature and the operating pressure of the ozone-generating system.
Over the last few years, as a result of technological progress with manufacturing tolerances increasingly smaller reaction gaps have been achieved, which influence both the field strength and the temperature established in the gap. Gap widths of 250 μm are now state of the art.
A device of the type specified initially is known from WO 97/09268. The device comprises an arrangement with at least one gap through which the gas flows, which is formed between an electrode and a dielectric that separates the gap from another electrode. At least one of the gaps is filled with an electrically conductive and thermally conductive gas-permeable arrangement which is in electrical and thermal contact with the adjacent electrode and through which the oxygen-containing gas flows and which forms a plurality of discharge spaces in which the oxygen-containing gas is exposed to a high field strength and is converted into ozone.
The electrically and thermally conductive gas-permeable arrangement described there at least completely fills one gap and preferably comprises wire which is constructed as knit.
By adapting the mesh number, mesh size, and wire thickness as well as the knit density, the number of knit wires and the number of knit layers, it is possible to establish the flow resistance of the arrangement, to adapt the size of the discharge spaces for maximal ozone production, to regulate the turbulence and intermixture of the gas, and to optimise cooling and heat dissipation.